非结合电子倒置驱动结构工程:对线性和非线性光学性质的协同增强
Jia-Xiang Zhang1,2,3, Sheng-Hua Zhou1,2,4, Xin-Tao Wu1,2
1State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China.
Angewandte Chemie (International ed. in English)
|April 28, 2025
概括
研究人员开发了一种新的策略,使用非结合电子来创建具有大双折射率和强大的非线性光学特性的晶体. 这一突破为设计先进光学材料提供了新的途径.
科学领域:
- 材料科学 材料科学 材料科学
- 晶体学 晶体学是指结晶学.
- 非线性光学是非线性光学.
背景情况:
- 在晶体中同时优化大双折射率 (Δn) 和强的第二和生成 (SHG) 是由于相互冲突的结构需求而具有挑战性.
- 在光学属性四面体堆叠中,沿轴的非结合电子的作用仍然未被充分探索.
研究的目的:
- 引入一种新的非结合电子逆转策略,以克服缺陷钻石状结构中的相匹配限制.
- 为了合成和表征一种新的晶体,[Ba4Cl2][CdGa4S10],用于增强线性和非线性光学特性.
主要方法:
- 在晶体结构中加入T2-[Ga4S10]超四面体图案.
- [Ba4Cl2][CdGa4S10]与空间组I的合成 .
- 光学属性的表征,包括双折射,SHG,传输范围,带隙和激光诱导损伤值.
主要成果:
- 与Cd2GaS4相比,达到了 Δn 的 219% 的提高.
- 证明了强烈的SHG反应,归因于弱结合的无结合电子.
- 这种新材料具有广泛的传输范围 (0.28-18.6μm),高激光诱导损伤值,宽带间隙 (3.58 eV) 和大SHG (1.4 × AgGaS2).
结论:
- 非结合性电子逆转策略成功平衡了宽带间隙和大SHG,产生了最好的Cd基NLO材料之一.
- 引入了基于非结合性电子驱动结构-属性关系的第一阶段匹配设计策略.
- 为高性能非线性光学材料的合理设计提供了关键的见解.
相关概念视频
01:07Nuclear Overhauser Enhancement (NOE)
578
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the Nuclear Overhauser Enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring...
578
02:52Stereoisomerism
11.6K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
11.6K
01:26Photochemical Electrocyclic Reactions: Stereochemistry
1.8K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
1.8K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
1.3K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
1.3K
02:42Valence Bond Theory
8.3K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.3K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
40.7K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
40.7K